The invention relates to an actuating device for a turbine of an exhaust gas turbocharger particularly for controlling the charging pressure of the exhaust gas turbocharger.
Such an actuating device is disclosed for example in US 2003/0196435 A1. The actuating device which serves to control the charging pressure of the exhaust gas turbocharger comprises a first bolt element which is rotatable about an axis of rotation. A valve element, a so-called waste gate, of the turbine is movable between a closed position and at least one open position via the first bolt element.
In the open position, the valve element opens a bypass duct, a so-called waste gate duct. The exhaust gas may bypass a turbine wheel of the turbine via the bypass duct so that the turbine wheel is not driven by the exhaust gas. The output of the turbine and thus the charging pressure of the exhaust gas turbocharger may be controlled by opening and closing of the bypass duct.
The first bolt element is non-rotatably joined to a connecting element, in this case to a connecting plate. The connecting element is articulatedly joined to an actuating element via a second bolt element. Here, the actuating element and the connecting element are joined rotatably about another axis of rotation relative to each other, with the axis of rotation and the other axis of rotation extending at least essentially parallel to each other. The actuating element is movable at least essentially vertically and translatorily to the axis of rotation of the first bolt element.
By moving the actuating element translatorily, the first bolt element is rotated about its axis of rotation due to the connection of the actuating element with the connecting element as well as due to the connection of the connecting element with the first bolt element. This is accompanied by the movement of the valve element of the turbine.
It was found that in particular due to wear as well as due to manufacturing-related tolerances some play between the connecting element and the bolt elements may develop which results in the generation of noises.
It is therefore the object of the present invention to develop an actuating apparatus for a turbine of an exhaust gas turbocharger of the above mentioned type in such a manner that the turbine noises are at least reduced.